Drug therapy began in the 1930s; since the 1970s, stimulants such as dexamphetamine, and methylphenidate have increasingly been used as the treatment of choice, but remain controversial. Currently available psychological treatments for ADHD include behavioural training for teachers and parents, and parenting skills classes, behavioural therapy for children with ADHD. Psychosocial treatments are generally combined with medication because each treatment alone has only a partial effect on the core symptoms of the disorder.